Alternating current (AC) generators are used for myriad applications, for example, in a gas turbine engine, such as that found in aircraft, ships, and some terrestrial vehicles. These generators may include three separate brushless generators, namely, a permanent magnet generator (PMG), an exciter, and a main generator. Each of these generators may include rotors and stators. When the rotor rotates, AC currents are induced in stator windings of the generator.
Periodically, an AC generator may need to undergo static and dynamic electrical performance testing. The test results allow an operator to determine the electrical integrity of the wires and/or coils therein and to assess the scope of repair or overhaul that the generator may need to undergo. Accordingly, the AC generator first may be separated from the engine and temporarily mounted to a test stand. Multiple test instruments are connected to the appropriate sections of the AC generator to obtain the appropriate readings therefrom.
Although conventional methods of testing electrical integrity of AC generators have been effective, these methods suffer from certain drawbacks. For example, typically, the exciter rotor is not directly tested. Instead, measurements for surrounding components are obtained and test data relating to the exciter rotor are calculated therefrom. As a result, the calculation may not be as accurate as desired. Additionally, because the exciter rotor is typically accessed and bench-tested while it is inactive, the condition of the exciter rotor during operation may not be assessed correctly. In either case, the operator may conclude that the exciter rotor, and hence, the AC generator, needs a larger scope of repair or overhaul than needed, which may unnecessarily increase the cost of repair.
Hence, there is a need for a device for testing an AC generator that is capable of directly testing the AC generator rotor. Additionally, it is desirable to have a device that is capable of assessing the condition of the generator during operation. The present invention addresses one or more of these needs.